As long as the person has an active ID card and is currently overseas you can order from the program.

The ID card holder could purchase the BMW, but non-card holders in the family could not, to further clarify.

To "escape" certain taxes, the car would also have to be registered in Europe for 6 months (I think) prior to sending it back to the US. For those that are stationed in Europe, the deal is quite good. For those that are ordering from downrange and then accepting delivery in the US, typically it is a little less of a great deal due to the added duties/taxes.